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    <script>
        // console.log(a,b)
        // console.log( + "120")
        // console.log(Boolean("a"))

        // 换位置
        var a = 11;
        var b = 13;
        console.log(a,b);
        var tmp = a;
        a = b;
        b = tmp;

        // 作业1 不考虑四舍五入的情况, 对一个数字进行保留三位小数
        var origin = 100.23456789
        var a = parseInt(origin * 1000 ) / 1000;
        console.log(a)
        
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